Most of my local Viking and Bernina dealers are very good about trade-ins and will give full credit for up to one year.
My Babylock/Pfaff dealer, who has a monopoly on Babylock in my area, is terrible - I was offered a measly $400 trade-in on my four month old, $2,000 machine. Needless to say, I won't be buying from them again. Even Babylock corporate was surprised and suggested I try some dealers out of town.